FireSub

Firesub is a Firebase Functions helper to easily publish Firestore or Storage events to PubSub.

There will be a case where you want handle all of your Firestore or Storage events in a single (monolithic) app instead of handle them separately as collection of microservices (Firebase Functions). Also it will also useful if you want to handle those events outside of GCP environment.

Firesub will helps you to build the bridge between the events and the worker that process the events. Allows you to be more flexible to design your system infrastructure and process the event with the language of your choice.

Note: Firesub is not a standalone service, it provides you helper functions to make it easily for you to create the "bridge". The bridge it self will be just a normal Firebase Functions but Firesub will helps creating them a breeze.

Install

npm install --save firesub

Quick Start

We'll create a couple of Firebase Functions that will publish an event when:

• A new document created on your Firestore collection
• A file has been uploaded into your Cloud Storage bucket

const admin = require('firebase-admin')
const firesub = require('firesub')

admin.initializeApp()

exports.postCreated = firesub.FirestoreOnCreate('/posts/{id}', 'topic_foo')
exports.fileUploaded = firesub.StorageOnFinalize('my-gs-bucket', 'topic_bar')

Deploy them:

firebase deploy --only functions

When all are good you will have two Firebase Functions (postCreated, fileUploaded) deployed and ready to push events to PubSub topics of your choosing.

Please note that all of those PubSub topic must be created first before you able to publish messages into it.

Available Events

Currently it's only available for Firestore and Cloud Storage events, but I might add more in the future.

GCP Products	Events	Description
Firestore	FirestoreOnWrite	when document created or updated or deleted
	FirestoreOnCreate	when document created
	FirestoreOnUpdate	when document updated
	FirestoreOnDelete	when document deleted
Storage	StorageOnFinalize	when a new file is created (or an existing object is overwritten, and a new generation of that object is created) in the bucket
	StorageOnArchive	when a live version of an object is archived or deleted
	StorageOnDelete	when a file is permanently deleted
	StorageOnMetadataUpdate	when the metadata of an existing object changes

More info about Firestore trigger events here and more about Cloud Storage trigger events here

PubSub Message Format

Below are message formats that are published to topic for each event type.

FirestoreOnWrite, FirestoreOnUpdate

{
   "id": "document ID",
   "timestamp": "2020-03-21T04:24:15.789595Z",
   "before": {... document before ...},
   "after": {... document after ...}
}

FirestoreOnCreate, FirestoreOnDelete

{
   "id": "document ID",
   "timestamp": "2020-03-21T04:24:15.789595Z",
   "data": {... document that created or deleted ...}
}

StorageOnFinalize, StorageOnArchive, StorageOnDelete, StorageOnMetadataUpdate

{
   "file": {... file information ...},
   "context": {... event context ...}
}

Example usage

You could see example project here

Contribution

This is young project, created because I need it for my own project thats why the events that are supported is very limited at this stage. If you would like it to support more events your contribution are welcome.

License

MIT License

Copyright (c) 2020 Eka Putra

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